Improved Printer Fingerprinting

Some additional information with the challenges of scanning printers, not just with Tenable products, but any type of scanner.

Ports of concern:

PORT 9100
Most printers use AppSocket, also known as Port 9100, RAW, JetDirect, or Windows TCPmon which is a protocol that was developed by Tektronix.
It is considered as 'the simplest, fastest, and generally the most reliable network protocol used for all printers' though 'it also offers no security and is often an attack vector with printers'
When they say attacked, this can just mean that they are sent TCP packets that make them print rubbish out, thus effectively doing a Denial of Service attack.

PORT 515
The Line Printer Daemon protocol/Line Printer Remote protocol (or LPD, LPR) is a network protocol for submitting print jobs to a remote printer. The original implementation of LPD was in the Berkeley printing system in the 2.10 BSD UNIX operating system in 1988; the LPRng project also supports that protocol. The LPD Protocol Specification is documented in RFC 1179.LPD printing normally happens over port 515.

PORT 631
The Internet Printing Protocol (IPP) is an Internet protocol for communication between client devices (computers, mobile phones, tablets, etc.) and printers (or print servers). IPP can run locally or over the Internet. Unlike other printing protocols, IPP also supports access control, authentication, and encryption, making it a much more capable and secure printing mechanism than older ones. IPP is supported by over 98% of printers sold today. IPP printing normally happens over port 631. It is the default protocol in Android and iOS.